Today, mobile networks and mobile devices enable applications for millions of users in diverse network environments. However, the potential of mobile networks has not
not yet been fully realized because such networks are often unreliable and prone to disconnection. Mobile network environments, ranging from well-connected mesh networks to extremely sparse Delay Tolerant Networks (DTNs), face a variety of connectivity challenges due to unpredictable links, coverage holes, and losses in the wireless medium.

In this talk, I will present a suite of protocols that overcome unreliability and improve connectivity in diverse mobile networks. At one end of the connectivity spectrum are sparsely connected DTNs, where the lack of an end-to-end path causes traditional routing protocols to break down. I will present RAPID, a DTN routing protocol that uses opportunistic replication coupled with a utility-driven algorithm to significantly improve a given routing metric. At the other end of the spectrum are well-connected mesh networks, where factors such as multipath fading lead to short disruptions that affect performance of interactive applications such as Voice over IP. I will present ViFi, a mesh network protocol that reduces disruptions using a probabilistic relaying algorithm that leverages overheard packets. Using RAPID and ViFi as examples, I will show how utility-driven and probabilistic algorithms can be used to implement protocols in a decentralized and highly uncertain wireless environment. Our deployment and experimental evaluation of these protocols in outdoor mobile testbeds demonstrate the effectiveness of our approach.

I will briefly describe some of my more recent works on improving energy efficiency in mobile devices. Finally, I will conclude by outlining future research challenges in designing self-adapting protocols to allow seamless operation and in improving the usability of next generation mobile devices.

Bio: Aruna Balasubramanian is a fifth year PhD candidate at the University of Massachusetts Amherst in the Department of Computer Science. Her research interests are broadly in systems and networking. She is specifically interested in mobile and sensor systems, delay tolerant networks, and energy efficiency. Her current research focus is on building robust wireless protocols that allow mobile access in diverse network environments. Her work has appeared in such conferences as ACM Sigcomm and ACM Mobicom. She is a Program Committee Co-chair for the Ph.D Forum held in conjunction with ACM MobiSys 2010, and was the General Co-Chair for the 2009 PhD Forum. She was a Program Committee Member of ACM CHANTS 2009. She is the recipient of a Microsoft Graduate Research Fellowship.